TO MEASURE THE CAPACITY OF AN" ORGAN. 135 



When the organ is perfectly dry, the ends containing the corks 

 may be cut off, and fresh corks secured with mucilage only. In at 

 least one of the corks should be a screw-eye to which the label may 

 be attached, and by which the specimen may be suspended from a 

 screw-hook. 



Finally, by excising one or more pieces of the wall with a keen 

 scalpel, the position and shape of the orifices may be displayed. 



A. Dried inflated specimens should be kept free from dust and moisture, in close cases, 

 or boxes or jars. They shovld not be ■varnished. 



B. Inflated preparations which have been dried without poisoning, or have been insuf- 

 ficiently poisoned, may be sprayed with the solution of arseniate of soda by means of an 

 atonuzer. This should be done cautiously and over a small area at a time, lest the entire 

 organ collapse. 



C. According to a paragraph in the " American Naturalist " for March, 1881, page 383, 

 " Dry specimens may be freed from parasites by spraying with anhydrous sulphurous acid." 



§ 334. To measure the Capacity of an Organ. — This may be 

 done in either of two ways : — 



1. The organ may be filled with water from a vessel of known 

 capacity, and the amount measured. 



2. The organ may be filled, and its contents allowed to escape 

 into a vessel and then measured. 



In employing either method, certain precautions should be ob- 

 served : — 



1. The organ should be completely emptied of its contents. 



2. It should not be measured until after the cessation of any 

 contraction which may exist at or soon after death. 



8. If possible, it should be held by an assistant. 



4. It should rest in a dish of water so that the water used in 

 measuring may not exert undue pressure. 



5. Since only the capacity of the organ itself is desired, care 

 must be taken to let the water go no farther than the outlets. With 

 the stoma-ch, for example, the pylorus should be closed, and the 

 introduced water should not rise into the oesophagus. 



6. If the organ is not to be preserved, the pylorus may be tied. 

 But as tying injures the parts, a specimen which is to be preserved 

 may have the outlet held by an assistant or closed by a compressor 

 or by other mechanical means. 



7. If the cardiac orifice is large, the water may be poured in. 

 If small, it may be introduced through a tunnel or through a can- 

 ula connected with a syringe. In the one case hydrostatic pressure 



